Hello,
This is v4 of cgroup writeback support patchset. Changes from the
last take[L] are
* b9ea25152e56 ("page_writeback: clean up mess around
cancel_dirty_page()") replaced cancel_dirty_page() with
account_page_cleaned() which pushed clearing the dirty flag to the
caller; however, changes in this patchset and the following ones
require synchronization between dirty clearing and stat updates
which is a lot easier with a helper which does both operations.
0001-page_writeback-revive-cancel_dirty_page-in-a-restric.patch is
added to resurrect cancel_dirty_page() in a more restricted form.
* Recent dirtytime changes added wakeup_dirtytime_writeback() which
needs to be updated to walk through all wb's.
0042-writeback-make-wakeup_dirtytime_writeback-handle-mul.patch
added.
* Rebased on top of the current block/for-4.2/core.
blkio cgroup (blkcg) is severely crippled in that it can only control
read and direct write IOs. blkcg can't tell which cgroup should be
held responsible for a given writeback IO and charges all of them to
the root cgroup - all normal write traffic ends up in the root cgroup.
Although the problem has been identified years ago, mainly because it
interacts with so many subsystems, it hasn't been solved yet.
This patchset finally implements cgroup writeback support so that
writeback of a page is attributed to the corresponding blkcg of the
memcg that the page belongs to.
Overall design
--------------
* This requires cooperation between memcg and blkcg. Each inode is
assigned to the blkcg mapped to the memcg being dirtied.
* struct bdi_writeback (wb) was always embedded in struct
backing_dev_info (bdi) and the distinction between the two wasn't
clear. This patchset makes wb operate as an independent writeback
execution domain. bdi->wb is still embedded and serves the root
cgroup but there can be other wb's for other cgroups.
* Each wb is associated with memcg. As memcg is implicitly enabled by
blkcg on the unified hierarchy, this gives a unique wb for each
memcg-blkcg combination. When memcg-blkcg mapping changes, a new wb
is created and the existing wb is unlinked and drained.
* An inode is associated with the matching wb when it gets dirtied for
the first time and written back by that wb. A later patchset will
implement dynamic wb switching.
* All writeback operations are made per-wb instead of per-bdi.
bdi-wide operations are split across all member wb's. If some
finite amount needs to be distributed, be it number of pages to
writeback or bdi->min/max_ratio, it's distributed according to the
bandwidth proportion a wb has in the bdi.
* cgroup writeback support adds one pointer to struct inode.
Missing pieces
--------------
* It requires some cooperation from the filesystem and currently only
works with ext2. The changes necessary on the filesystem side are
almost trivial. I'll write up a documentation on it.
* blk-throttle works but cfq-iosched isn't ready for writebacks coming
down with different cgroups. cfq-iosched should be updated to have
a writeback ioc per cgroup and route writeback IOs through it.
How to test
-----------
* Boot with kernel option "cgroup__DEVEL__legacy_files_on_dfl".
* umount /sys/fs/cgroup/memory
umount /sys/fs/cgroup/blkio
mkdir /sys/fs/cgroup/unified
mount -t cgroup -o __DEVEL__sane_behavior cgroup /sys/fs/cgroup/unified
echo +blkio > /sys/fs/cgroup/unified/cgroup.subtree_control
* Build the cgroup hierarchy (don't forget to enable blkio using
subtree_control) and put processes in cgroups and run tests on ext2
filesystems and blkio.throttle.* knobs.
This patchset contains the following 51 patches.
0001-page_writeback-revive-cancel_dirty_page-in-a-restric.patch
0002-memcg-add-per-cgroup-dirty-page-accounting.patch
0003-blkcg-move-block-blk-cgroup.h-to-include-linux-blk-c.patch
0004-update-CONFIG_BLK_CGROUP-dummies-in-include-linux-bl.patch
0005-blkcg-always-create-the-blkcg_gq-for-the-root-blkcg.patch
0006-memcg-add-mem_cgroup_root_css.patch
0007-blkcg-add-blkcg_root_css.patch
0008-cgroup-block-implement-task_get_css-and-use-it-in-bi.patch
0009-blkcg-implement-task_get_blkcg_css.patch
0010-blkcg-implement-bio_associate_blkcg.patch
0011-memcg-implement-mem_cgroup_css_from_page.patch
0012-writeback-move-backing_dev_info-state-into-bdi_write.patch
0013-writeback-move-backing_dev_info-bdi_stat-into-bdi_wr.patch
0014-writeback-move-bandwidth-related-fields-from-backing.patch
0015-writeback-s-bdi-wb-in-mm-page-writeback.c.patch
0016-writeback-move-backing_dev_info-wb_lock-and-worklist.patch
0017-writeback-reorganize-mm-backing-dev.c.patch
0018-writeback-separate-out-include-linux-backing-dev-def.patch
0019-bdi-make-inode_to_bdi-inline.patch
0020-writeback-add-gfp-to-wb_init.patch
0021-bdi-separate-out-congested-state-into-a-separate-str.patch
0022-writeback-add-CONFIG-BDI_CAP-FS-_CGROUP_WRITEBACK.patch
0023-writeback-make-backing_dev_info-host-cgroup-specific.patch
0024-writeback-blkcg-associate-each-blkcg_gq-with-the-cor.patch
0025-writeback-attribute-stats-to-the-matching-per-cgroup.patch
0026-writeback-let-balance_dirty_pages-work-on-the-matchi.patch
0027-writeback-make-congestion-functions-per-bdi_writebac.patch
0028-writeback-blkcg-restructure-blk_-set-clear-_queue_co.patch
0029-writeback-blkcg-propagate-non-root-blkcg-congestion-.patch
0030-writeback-implement-and-use-inode_congested.patch
0031-writeback-implement-WB_has_dirty_io-wb_state-flag.patch
0032-writeback-implement-backing_dev_info-tot_write_bandw.patch
0033-writeback-make-bdi_has_dirty_io-take-multiple-bdi_wr.patch
0034-writeback-don-t-issue-wb_writeback_work-if-clean.patch
0035-writeback-make-bdi-min-max_ratio-handling-cgroup-wri.patch
0036-writeback-implement-bdi_for_each_wb.patch
0037-writeback-remove-bdi_start_writeback.patch
0038-writeback-make-laptop_mode_timer_fn-handle-multiple-.patch
0039-writeback-make-writeback_in_progress-take-bdi_writeb.patch
0040-writeback-make-bdi_start_background_writeback-take-b.patch
0041-writeback-make-wakeup_flusher_threads-handle-multipl.patch
0042-writeback-make-wakeup_dirtytime_writeback-handle-mul.patch
0043-writeback-add-wb_writeback_work-auto_free.patch
0044-writeback-implement-bdi_wait_for_completion.patch
0045-writeback-implement-wb_wait_for_single_work.patch
0046-writeback-restructure-try_writeback_inodes_sb-_nr.patch
0047-writeback-make-writeback-initiation-functions-handle.patch
0048-writeback-dirty-inodes-against-their-matching-cgroup.patch
0049-buffer-writeback-make-__block_write_full_page-honor-.patch
0050-mpage-make-__mpage_writepage-honor-cgroup-writeback.patch
0051-ext2-enable-cgroup-writeback-support.patch
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-cgroup-writeback-20150522
diffstat follows. Thanks.
Documentation/cgroups/memory.txt | 1
block/bio.c | 35
block/blk-cgroup.c | 124 -
block/blk-cgroup.h | 603 --------
block/blk-core.c | 70 -
block/blk-integrity.c | 1
block/blk-sysfs.c | 3
block/blk-throttle.c | 2
block/bounce.c | 1
block/cfq-iosched.c | 2
block/elevator.c | 2
block/genhd.c | 1
drivers/block/drbd/drbd_int.h | 1
drivers/block/drbd/drbd_main.c | 10
drivers/block/pktcdvd.c | 1
drivers/char/raw.c | 1
drivers/md/bcache/request.c | 1
drivers/md/dm.c | 2
drivers/md/dm.h | 1
drivers/md/md.h | 1
drivers/md/raid1.c | 4
drivers/md/raid10.c | 2
drivers/mtd/devices/block2mtd.c | 1
drivers/staging/lustre/lustre/include/linux/lustre_patchless_compat.h | 4
fs/block_dev.c | 9
fs/buffer.c | 64
fs/ext2/super.c | 2
fs/ext4/extents.c | 1
fs/ext4/mballoc.c | 1
fs/ext4/super.c | 1
fs/f2fs/node.c | 4
fs/f2fs/segment.h | 3
fs/fat/file.c | 1
fs/fat/inode.c | 1
fs/fs-writeback.c | 619 ++++++--
fs/fuse/file.c | 12
fs/gfs2/super.c | 2
fs/hfs/super.c | 1
fs/hfsplus/super.c | 1
fs/inode.c | 1
fs/mpage.c | 2
fs/nfs/filelayout/filelayout.c | 1
fs/nfs/internal.h | 2
fs/nfs/write.c | 3
fs/ocfs2/file.c | 1
fs/reiserfs/super.c | 1
fs/ufs/super.c | 1
fs/xfs/xfs_aops.c | 12
fs/xfs/xfs_file.c | 1
include/linux/backing-dev-defs.h | 188 ++
include/linux/backing-dev.h | 567 +++++---
include/linux/bio.h | 3
include/linux/blk-cgroup.h | 631 +++++++++
include/linux/blkdev.h | 21
include/linux/cgroup.h | 25
include/linux/fs.h | 13
include/linux/memcontrol.h | 10
include/linux/mm.h | 7
include/linux/pagemap.h | 3
include/linux/writeback.h | 25
include/trace/events/writeback.h | 8
init/Kconfig | 5
mm/backing-dev.c | 666 +++++++--
mm/fadvise.c | 2
mm/filemap.c | 31
mm/madvise.c | 1
mm/memcontrol.c | 59
mm/page-writeback.c | 696 +++++-----
mm/readahead.c | 2
mm/rmap.c | 2
mm/truncate.c | 18
mm/vmscan.c | 28
72 files changed, 3054 insertions(+), 1578 deletions(-)
--
tejun
[L] http://lkml.kernel.org/g/1428350318-8215-1-git-send-email-tj@xxxxxxxxxx
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